If your BWC deployment is used for a sufficiently long period of time or
you have a lot of executions happening/triggers coming in, the database fills up.
If you are looking for a way to purge old data in bulk for performance reasons
or cleaning up the DB, you have two options described below.

By default, only executions in completed state, i.e. succeeded, failed, canceled, timeout
and abandoned are deleted. If you want to purge all models irrespective of status,
you can pass the --purge-incomplete option to the script.